KR100848309B1 - Apparaus and method of providing internet TV brodacasting service using fast buffering switch - Google Patents

Abstract

The present invention relates to an apparatus and method for providing an internet broadcast service using a high speed buffering switch. The present invention relates to a channel message processing unit for requesting a broadcast server to transmit streaming data on a broadcast channel through an access network to which a user terminal requesting broadcast channel reception is connected. And a data storage unit for generating or deleting a logical stream buffer, and receiving the streaming data for the requested broadcast channel from the broadcast server, and creating a stream buffer in the data storage unit to store the received streaming data. It is composed of a processing unit and a broadcast stream output unit for copying the stored streaming data in real time to make a multicast broadcast to the user terminal, the video terminal to the initial streaming data for a predetermined time when the Internet broadcast receiver switch channel It improves the buffering delay caused by storing in the buffer memory so that faster buffering can be achieved, thereby enabling faster channel switching.

Internet broadcasting, channel change delay, high speed buffering

Description

Method and apparatus for providing internet broadcasting service using fast buffering switch TECHNICAL FIELD

1 is a view for explaining a conventional method for reducing the delay caused by the buffering of streaming data in the user terminal in a video on demand (VoD) service network.

2 is a diagram illustrating an encoding method used by MPEG (Motion Pictures Expert Group) for compressing digitized video image data, and a channel change delay occurring due to encoding characteristics of MPEG.

3 is a diagram illustrating a broadcast service apparatus using a fast buffering switch according to an embodiment of the present invention.

4 is a flowchart illustrating a method for processing streaming data received from a broadcast server through an internet network according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating a method of receiving a channel request message from a broadcast receiving subscriber and providing streaming data corresponding to the requested channel according to an embodiment of the present invention.

An object of the present invention is to provide an internet broadcasting service providing a plurality of streaming channels. More specifically, the present invention provides a high speed buffering switch for improving a channel change delay phenomenon in which an initial video screen appears more than a few seconds later when a viewer changes a channel stream. The present invention relates to an apparatus and method for using an internet broadcasting service.

An internet broadcasting service refers to a service that provides multimedia data, ie, video or audio data, to a user in real time or through a video on demand (VOD) service through an internet network.

In providing such an Internet broadcast service, since a connection line with a high transmission speed is not guaranteed to immediately transmit a large amount of video or audio data, data is divided into several files and transmitted in real time. Even before all files are transferred, a streaming service is used that allows a browser or plug-in program to start presenting (playing) the received data on the client system.

However, if you want to send streaming traffic through the Internet network where the quality of the bandwidth required by the broadcasting service is not certain, due to the unexpected traffic congestion on the transmission path, the streaming rate of the streaming traffic is uneven and the packet flow sometimes occurs. Congestion or delayed jitter may occur, resulting in intermittent broadcast interruptions. In general, the commercial Internet broadcast receiving terminal prevents the jitter phenomenon caused by the jitter by storing the streaming data in the internal large buffer memory for a predetermined time and then reproducing the image before playing the image. The larger the buffer memory of the terminal, the greater the storage of streaming data, the greater the buffering effect on jitter in the network, but the more time it takes to store streaming data in the buffer memory (more than a few seconds). Nothing is displayed on the video screen. If a user wants to search for dozens of broadcast channels and select the ones they like, like watching a typical cable TV service, every time they change, they have to request a new streaming channel and wait a few seconds or more for the buffer memory to fill up. This causes the user to feel uncomfortable.

A conventional technique for reducing the channel change delay time caused by the time of filling the buffer memory of the video terminal with the streaming data is disclosed in FIG. 1.

Referring to FIG. 1, a user who wants to receive real-time streaming data from a video on demand (VOD) server 140 transmits a signal message that records information on a channel to be received to a VoD server using a video terminal 110. do. When the VoD server 140 receives the channel request signal from the user, the VoD server 140 transmits the data at the maximum transmission rate 120 as long as the communication network 130 permits, while being higher than the original encoding rate of the streaming data.

Therefore, the buffer memory 111 of the video terminal 110 of the user is initially filled at a speed faster than the encoding speed (encoding speed). The video terminal 110 of the user monitors the amount of data filled in the buffer memory and transmits a signal message requesting the transmission rate to be reduced toward the VoD server 140 at the moment when the buffer memory is filled above a predetermined level.

The VoD server 140 receiving the transmission rate reduction request message lowers the data transmission rate to transmit data according to the original encoding rate of the streaming data. As a result, the video terminal 110 of the user fills the buffer memory required for initial screen startup at a high speed and starts the decoding process more quickly, thereby minimizing delay due to channel switching.

However, the method of the above patent is a method applicable only to one-to-one unicast communication in which the VoD server 140 and the video terminal 110 can exchange messages with each other and adjust a transmission rate, such as a VoD service. Likewise, in the case of multicast communication in which a single broadcast server copies and transmits stream data to a plurality of receivers at the same time, there is a problem that application is complicated.

That is, in the case of real-time multicast communication, when a new receiver wants to receive a replicated data stream by joining a receiving group, and if the initial buffer memory is to be filled quickly as in the method shown in FIG. 1, the broadcast server uses a separate communication channel. It requires the function to collect the contents before or after the current frame and send them at high speed, which makes the implementation of the broadcasting server more complicated.

Therefore, when a plurality of receivers simultaneously receive a multicast broadcast stream such as a real-time Internet broadcast service, the contents disclosed in FIG. 1 may not be applied as it is.

 2 is a diagram illustrating an encoding method used by MPEG (Motion Pictures Expert Group) for compressing digitized video image data, and a channel change delay phenomenon caused by MPEG encoding characteristics.

Referring to FIG. 2, MPEG compresses digitized video image data frames into different formats such as I-frame (Intra frame), P-frame (Predictive frame), and B-frame (Bi-directional frame). While the I-frames 210 and 220 have the lowest compression rate of image data compared to other types of frames, the I-frames 210 and 220 may independently reconstruct image data without depending on information of other frames.

On the other hand, the P-frame extracts and encodes only the information on the change of motion based on the image information of the I-frame, and since the B-frame only contains information that compensates for the difference in motion between the scenes before and after, the data compression ratio is higher. That is, the I-frames 210 and 220 serve as keys for interpreting the P-frame and B-frame 230 information. Scenes corresponding to the B-frame cannot be restored (250).

For this reason, in order to minimize video loss due to damage of key-frames, key-frames (i.e., I-frames) are frequently generated periodically and inserted into the data stream, or video scenes are displayed for each scene where a sudden change occurs. Encode by encoding key-frame (ie, I-frame).

For example, as shown in FIG. 2, the broadcast server broadcasts streaming data by generating I-frames 210 and 220 serving as keys by using the MPEG encoding scheme in units of 1 second. If the channel reception request message transmitted from a receiver arrives after the I-frame has already been transmitted by the broadcast server (240), the video information is decoded even if the receiver receives the P-frame or B-frame transmitted thereafter. And all are discarded (250), and the receiver must wait until the next I-frame arrives (260).

Therefore, if an I-frame is generated at an interval of 1 second, an average delay of 0.5 seconds or a maximum of 1 second may additionally occur every channel change due to encoding characteristics such as MPEG.

The technical problem to be achieved by the present invention is a packet-based Internet broadcasting service environment that transmits a plurality of streaming data by the multicast transmission method, a delay of several seconds or more until the initial screen is activated when the user changes the Internet broadcasting reception channel The present invention provides a method and apparatus for providing an internet broadcasting service in which a quick channel change is made by improving a disadvantage of a conventional channel change method.

In accordance with another aspect of the present invention, there is provided an apparatus for providing an internet service using a fast buffering switch, which requests streaming data transmission for a broadcast channel to a broadcast server through an access network to which a user terminal requesting broadcast channel reception is connected. A channel message processing unit, a data storage unit for generating or deleting a logical stream buffer, receiving streaming data for the requested broadcast channel from the broadcast server, and generating a stream buffer in the data storage unit to store the received streaming data. And a broadcast stream output unit configured to copy the broadcast stream processing unit and the stored streaming data, and transmit the multicast broadcast to the user terminal in real time.

The broadcast stream processor may attach a key frame identifier and store the generated stream buffer in the generated stream buffer when the received streaming data includes a key frame.

The broadcast stream processor may delete streaming data from a start point of the streaming data stored in the stream buffer to a point to which a next key frame identifier is attached when the amount of data stored in the stream buffer is greater than or equal to a predetermined threshold.

The broadcast stream processor may generate a stream buffer in the data storage unit when the stream buffer of the data storage unit corresponding to the broadcast channel requested by the user terminal does not exist, and when the stream buffer exists, the stream The streaming data stored in the buffer is characterized in that the transmission to the broadcast stream output unit.

In addition, the broadcast stream output unit transmits the streaming data at the maximum transmission rate allowed by the access network connected to the user terminal so that all the streaming data stored in the stream buffer can be transmitted. Receiving the streaming data for the broadcast channel from the stream processor for real-time copying and multicast forwarding.

The data storage unit may generate a plurality of stream buffers, and the broadcast stream output unit may transmit streaming data for broadcast channels required by a plurality of user terminals.

Internet service providing method using a high-speed buffering switch according to the present invention for solving the technical problem, (a) analyzing the streaming data received from the broadcast server to extract the frame type information, (b) of the streaming data Attaching a key frame identifier to the streaming data when the frame type is a key frame, (c) generating a stream buffer when there is no stream buffer capable of storing the streaming data, (d) the (c) Deleting the streaming data from the start point of the streaming data stored in the stream buffer to the point where the data with the next key frame identifier is present when the stream buffer is stored above a certain limit when the stream buffer exists. (e) generated in step (c) or in step (d) Storing the streaming data received from the broadcast server in the stream buffer from which data has been deleted; and (f) copying the streaming data stored in the stream buffer in step (e) and transmitting it to the user terminal. It is done.

In accordance with an aspect of the present invention, there is provided a method for providing an Internet service using a fast buffering switch, the method comprising: (a) transmitting a channel reception request message corresponding to a broadcast channel desired by an Internet broadcast service user, (b) the channel Extracting channel information by analyzing a reception request message; (c) determining whether a stream buffer corresponding to the channel is generated, and if not generated, transmitting the channel reception request message to a broadcast server through an upstream node; (D) if the stream buffer exists and the streaming data for the broadcast channel is stored, transmitting the streaming data stored in the stream buffer at the maximum transmission rate allowed by the user terminal to the connected access network; and (ㅁ) the stream. After all the streaming data stored in the buffer has been transferred And receiving the streaming data for the broadcast channel reproduced in real time from the broadcast server group is characterized by comprising: a multicast forwarding.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

3 is a diagram illustrating a broadcast service apparatus using a fast buffering switch according to an embodiment of the present invention. Referring to FIG. 3, the broadcast server 300 includes an Internet network 310, a high speed buffering switch 320, and subscriber stations 321 to 333.

The fast buffering switch 320 is connected to a broadcast server 300 that provides a broadcast stream through the Internet network 310, and the broadcast server 300 provides a broadcast stream of a corresponding channel according to a received channel request frame. .

The high speed buffering switch 320 may include a first interface means (not shown) that can access the broadcast server 300 through an internet network, and a second interface means (not shown) that can be connected to the IP-TV set-top box. Include.

The first interface means includes a broadcast stream processor 321 for processing a plurality of broadcast streams received from the broadcast server 300, and the second interface means broadcasts toward the subscriber stations 330, 331, 332, and 333. And a channel message processing unit 324 for processing the channel request message received from the subscriber station and the broadcast stream output unit 323 for copying and transmitting the stream.

In addition, the fast buffering switch 320 is characterized in that it comprises an internal storage area 322 that can store the streaming data by creating or deleting a plurality of logical stream buffers.

According to a preferred embodiment of the present invention, a process for processing the streaming data received from the broadcast server 300 through the high-speed buffering switch 320 is as follows.

The broadcast stream processor 321 of the fast buffering switch 320 analyzes the information of the streaming data received through the first interface means and extracts the channel information and the frame type information according to the encoding format.

In the analyzing step, the broadcast stream processor 321 attaches a key-frame identifier that can be recognized internally when the analyzed streaming data includes a frame (eg, an I-frame) corresponding to a key.

The broadcast stream processor 321 generates a logical stream buffer capable of storing stream data in the storage area if a logical stream buffer corresponding to the channel is not generated in the storage area 322 of the fast buffering switch.

If the stream buffer existing in the storage area 322 is above a certain threshold, the broadcast stream processing unit 321 examines the stored data from the start point of the stream buffer and stores the data to which the next key-frame identifier is attached. Delete the data.

The broadcast stream processor 321 stores the received streaming data in the stream buffer and copies the data to the broadcast stream output unit 323.

The broadcast stream output unit 323 transmits the streaming data in real time by multicast broadcasting to the channel receiver group.

In addition, according to an exemplary embodiment of the present invention, the broadcast receiving subscribers 330, 331, 332, and 333 receive a desired channel stream from the fast buffering switch 320 as follows. A case in which the first subscriber station 330 requests a broadcast channel will be described.

The user of the first receiving terminal 330 transmits a channel request message that records broadcast channel information to be received to the fast buffering switch 320 by manipulating the image receiving terminal.

The channel message processing unit 324 of the fast buffering switch 320 analyzes the channel request message received through the second interface means and extracts channel information.

The channel message processing unit 324 checks whether a logical stream buffer corresponding to the channel is generated in the storage area 322 of the fast buffering switch 320, and if there is no stream data stored in the stream buffer, the channel message message is sent. Transfer to the upstream node through the first interface means.

However, if there is a logical stream buffer corresponding to the channel in the storage area 322 of the fast buffering switch 320 and there is stored streaming data, the channel message processor 324 is stored in the broadcast stream processor 323. Request to send stream data.

The broadcast stream processor 323 transmits data stored in the stream buffer at the maximum data rate as long as the access network to which the first subscriber station 330 is connected is allowed.

When the stored streaming data transmission is completed, the broadcast stream processor 323 sets a multicast forwarding state capable of real time copying of the streaming data transmitted from the broadcast stream processor 321 to the first subscriber station 330.

Accordingly, when the Internet broadcast receiver 330, 331, 332, 333 requests channel conversion, the fast buffering switch 320 transmits streaming data stored in the storage area 322 at high speed to fill the buffer of the initial receiver terminal. In addition to reducing the buffering time, the streaming data encoded using a method such as MPEG is stored so that the key-frame can be transmitted first when stored in the storage area 322, so that the receiving terminal efficiently stores the image information. Make it decipherable.

4 is a flowchart illustrating a method for processing streaming data received from a broadcast server through an internet network according to an exemplary embodiment of the present invention.

The high speed buffering switch 320 analyzes the received streaming data information and extracts channel information and frame type information according to an encoding format (S400).

The high speed buffering switch 320 attaches a key-frame identifier that can be recognized internally when the analyzed streaming data includes a frame (eg, an I-frame) corresponding to a key (S410).

The fast buffering switch 330 generates a logical stream buffer capable of storing stream data in the storage area when the logical stream buffer corresponding to the channel is not generated in the internal storage area 322 (S430). (S440).

The high speed buffering switch 330 checks the stored data from the start point of the stream buffer when the stream buffer existing in the storage area 322 is greater than or equal to a predetermined threshold value (S450), and the data having the next key-frame identifier is present. The data stored up to the point is deleted (S460).

The fast buffering switch 330 stores the received streaming data in the stream buffer (S470).

The fast buffering switch 330 transmits the streaming data in real time by multicast broadcasting to the channel receiver group (S480).

5 is a flowchart illustrating a method of receiving a channel request message from a broadcast receiving subscriber and providing streaming data corresponding to the requested channel according to an embodiment of the present invention.

The subscriber requests a channel reception request message corresponding to a desired broadcast channel to the fast buffering switch 320 (S510).

The fast buffering switch 320 analyzes the received channel request message and extracts channel information (S520).

The high speed buffering switch 320 checks whether a logical stream buffer corresponding to the channel is generated in the internal storage area 322 (S530). If there is no stream data stored in the stream buffer, the high speed buffering switch 320 detects the channel request message. Forward to the upstream node (S550).

However, if there is a logical stream buffer corresponding to the channel in the storage area 322 of the fast buffering switch 320 and there is stored streaming data, as long as the communication network allows through the port receiving the channel request message. The data stored in the stream buffer is transmitted at the transmission rate (S540).

In addition, the fast buffering switch 320 sets a multicast forwarding state capable of delivering streaming data to the subscriber station requesting the channel reception in real time (S560).

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

In the present invention, in providing an Internet broadcasting service through a packet-based communication network, when the Internet broadcasting receiver switches channels, the buffering delay caused by the video terminal storing the initial streaming data in the buffer memory for a predetermined time is improved, thereby quickly buffering. This allows for faster channel switching.

In addition, when the video terminal receives streaming data encoded by a compression scheme such as MPEG, if it does not receive a frame that is a key from the beginning, the present invention discards all received P-frame or B-frame data and then It improves the inefficiency of waiting for key-frame to be received, so that the frame corresponding to the key per item can be transmitted first when channel switching, so that the subscriber's video terminal efficiently performs the decoding so that the faster channel switching is possible. As a result, Internet broadcast service users can feel smooth and comfortable in searching for broadcast channels and watching desired broadcasts.

Claims (9)

A channel message processing unit for requesting transmission of streaming data for the broadcast channel to a broadcast server through an access network to which a user terminal requesting a broadcast channel is connected; A data storage unit for generating or deleting a logical stream buffer; A broadcast stream processor configured to receive streaming data for the requested broadcast channel from the broadcast server, create a stream buffer in the data storage unit, and store the received streaming data; And And a broadcast stream output unit for copying the stored streaming data in real time to multicast broadcast to the user terminal. The method of claim 1, wherein the broadcast stream processing unit When the received streaming data includes a key frame, an apparatus for providing an internet broadcasting service using a high speed buffering switch, a key frame identifier is attached and stored in the generated stream buffer. The method of claim 2, wherein the broadcast stream processing unit When the amount of data stored in the stream buffer is greater than a predetermined threshold value, the streaming data from the start point of the streaming data stored in the stream buffer to the point to which the next key frame identifier is attached to provide an Internet broadcast service using a high-speed buffering switch Device. The method of claim 1, wherein the broadcast stream processing unit If a stream buffer of the data storage unit corresponding to the broadcast channel requested by the user terminal does not exist, a stream buffer is created in the data storage unit, and if the stream buffer exists, the streaming data stored in the stream buffer is read. Internet broadcast service providing apparatus using a high speed buffering switch characterized in that the transmission to the broadcast stream output unit. The method of claim 1, The broadcast stream output unit transmits the streaming data at the maximum transmission rate allowed by the access network connected to the user terminal so that all the streaming data stored in the stream buffer is transmitted, and when the transmission of the streaming data is completed, the broadcast stream processing unit Receiving the streaming data for the broadcast channel from the Internet broadcast service providing apparatus using a high-speed buffering switch, characterized in that the replication in real time multicast forwarding. The method of claim 1, And a data storage unit generates a plurality of stream buffers, and the broadcast stream output unit delivers streaming data for broadcast channels required by a plurality of user terminals. (a) extracting frame type information by analyzing streaming data received from a broadcast server; (b) attaching a key frame identifier to the streaming data when the frame type of the streaming data is a key frame; (c) creating a stream buffer when there is no stream buffer capable of storing the streaming data; (d) If the stream buffer exists in step (c), when the stream buffer is stored above a certain threshold, streaming from the beginning of the streaming data stored in the stream buffer to the point where the data with the next key frame identifier is present. Deleting the data; (e) storing the streaming data received from the broadcast server in a stream buffer generated in step (c) or in which data is deleted in step (d); And (f) copying the streaming data stored in the stream buffer in step (e) and transmitting the same to the user terminal. (A) transmitting a channel reception request message corresponding to a broadcast channel desired by the Internet broadcasting service user; (B) extracting channel information by analyzing the channel reception request message; (C) determining whether a stream buffer corresponding to the channel is generated, and if not, transmitting the channel reception request message to a broadcast server through an upstream node; (D) transmitting the streaming data stored in the stream buffer at the maximum transmission rate allowed by the user terminal to the connected access network if the stream buffer exists and the streaming data for the broadcasting channel is stored; And (ㅁ) receiving all the streaming data stored in the stream buffer and receiving the streaming data for the broadcast channel from the broadcast server to replicate in real time and multicast forwarding; including a high-speed buffering switch comprising a Internet broadcasting service providing method using. A computer-readable recording medium having recorded thereon a program for executing the method for providing an Internet broadcast service using the fast buffering switch as claimed in claim 7.

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